I have had a continual issue with an intermittent rough idle-like it's missing. There are no codes set, I have changed the fuel filter multiple times -there never has been any water in the fuel. The dealer looked at it when it was in for a recall, but of course it was idling fine, so they said nothing was wrong. Most of the time it will start idling rough after pulling up to a stop light, or sitting in the drive thru. Might do it all day, might only do it once or twice then be fine. This week it has started up rough a couple of times-like it's running on 3 or 4 cylinders for a minute or two, then it smooths out. Any ideas??

 

Mine has been doing this also. Runs perfect otherwise. It seems to happen when I'm below half a tank so I'm thinking it could be a fuel delivery restriction, but what do I know. Whats your fuel level when it happens?

 

Fuel level doesnt seem to matter. Just yesterday, it was doing fine as I was delivering some gifts to our customers and after about an hour it started idling rough- fuel level was above 3/4 tank. I had been keeping an eye on the fuel level trying to find some common occcurances in attempt to make some sort of starting point to diagnose the problem. I'm thinking it's something electrical the way it comes and goes. If it was a mechanical issue I think it would stay fairly constant or happen at the same time or set of circumstances (such as fuel level, temperature, etc.) There just really doesn't seem to be any rhyme or reason why it does it. I think I am going to go thru all of the electrical connnectors on the injection side of things and make sure they are clean and apply some dielectric grease to see if that does anything. I'll keep you posted.